Hydraulic diaphragm



Patented May 6,

- UNITED ,sTAT

mmuuc nmrnnso i nouns Chilton, mo ma. N. 1., by assignments, to Wright Aeronautical Corporation, Paterson, N. 1.. a corporation of New York Application November so, 1937, Serial No. 177,185

This invention relates to flexible or sealing means for reciprocating plungers sublejct to iluld pressure, the specific t of the drawing being suited for a hydraulic pres-' .sure measuring cell. The chief objects 01 the invention are to provide a diaphragm which shall combine great. flexibility for movement with cmnplete pressure tightness and with a maximum of volumetric fluid rigidity and pressure capacity. Other objects and advantages of the invention will be obvious from, or will be pointed out in, the following description with reference to the drawing in which,

Fig. 1 is an axial section through a hydraulic cell incorporating the invention;

Fig. 2 is afragmentary view of a partly formed diaph a m; 1

Fig. 3- is a cross section through a completely formed diaphragm. and

Fig. 4 is a fragmentary view illustrating the range oi action of the diaphragm.

Referring first to Fig. 1, l0 designates a housing having a cover plate l2 secured bybolts It so as to provide a hydraulically sealed joint with an interposed composite diaphragm it in which the. chief features of the invention reside. The

zcwms. (01. 131-451) in pure ion by the hydraulic pressure under which they will. naturally adopt a looped form between the plungerand housing, the radial pressures being resisted'by the piston head 29 and the bore ll of the housing I! towhich the annular loop 28 of the diaphragm is fitted.

The prefer-red method of manufacture of the diaphragm 24 consists in flrstslotting a thin metallic as, indicated in-Fig. 2 to provide clearances fl which become narrow when. the

' looped annulus" is formed in the diaphragm in suitable dies (not shown)- Preferably, these dies are arranged so that when the diaphragm hasbeen formed to the condition of Fig. ,3, a ri id metallic ring 34 is secured to the outer portions, as bysoldering} leaving the adjacent "ribbons of the annular looped part 28 with only suflicient clearance for the slight change in relative spacing required by the rolling action indicated in Fig. 4.

. purpom than weighing as, for example, to operate the plunger l8 by hydraulic pressure-or alternately, the novel diaphragm here disclosed housing it serves to guide a pressure rod l8 which engages a head 20 which rests upon the center portion or the composite diaphragm as shown. An orifice 22 is provided in the cover plate I! whereby the lower or pressure side of the diaphragm is hydraulically connected to the me ans'to be operated, which in this case comprises a pressure gauge (not shown) whereby the load on the rod ills to be measured.

The composite diaphragm it comprises a a metallic element 2! and a sealing element 28 of flexibleimpervious material, preferably oil 7 resistant rubber. Both the diaphragms consist of a list central portion the head 20 as shown and a rim portion clamped by'thecover plate I! as already described. The rim and central portions are connected by a torlc or looped annular element 28 and in the case or the metal element, this annulus is slotted to comprise a plurality of ribbons integral with the central portion 2i ribbons, by their slotted formation, are flexible to roll as indicated lung. 4 as the plunger 20 moves relative the housing II. The rubber diaphragm lies against the'iruid pressure side of the slotted metal diaphragm, thereby sealing the device againstleakage. 'The volumetric rigidity of "the assembi! resides in inextcnsible but pliable metal ribbon elements which it will be seen are stressed a is suitable for use in a reciprocating pump. 7

It will be seen that the looped elements 28, in mid position of the diaphragm have straight elements in their respective limbs and the range of action of the device is four tlmes the length of these straight elements. For very long strokes, it ispossible' that the rolling action be carried so far that a point on the metallic annulus which'at the downward end of the stroke contacts the plunger head 20 will; at the upward extreme. be transferred to contact the bore 30" of the housing. For these extreme travels it is necessary that the ribbons defined by the slots be parallel sided-and such slots will be virtually closed where the ribbon lies against the. inner plunger. The width of slot at the outer portion of the annulus then depends upon the relative width oi! this element. If this he, say 10% of the inner or plunger diameter, then the maximum gap or slot width will be 10% of the width of each ribbonand the rubber diaphragm must have sufllcient thickness to be capable of bridging this narrow slot under the operating hydraulic pressure; Alternately two slotted diaphragms. may be assembled in staggered overlying relationship so that the ribbons of one diaphragm bridge the slots of the other, whereby the sealing diaphragm II will have no tendency to extrude through the slots 32.

While I havedescribed my invention in detail in'its present preferred embodiment, it will be standing my-invention, that various changes and modifications may be made therein without departing from the spirit or scope thereoi. I aim in the appended claims to cover all such modiflcations and changes.

I claim as my invention:

1. In a seal tor a bored housing and drical plunger, a flexible diaphragm which comprises a radially slotted thin metallic disc, deflning between said slots radially extending ribbons a cylinwider than the slots, each of the several ribbons having a loop portion with straight sides normal to the disc plane. the summation of the several loops forming an annular groove in the disc by which the original diameter of the disc is reduced in virtue oi said loops, and a re-eniorcing ring secured around the outer ends or said ribbons, said ring and the central portion 01 said, disc respectively engaging the housing and piling-- er and being adapted for axial displacement with consequent rolling shift of the loop relative to the ring and central portion; the straight sides of the loops engaging the side walls oi the housing and the plunger, said radial slots being-reduced from their original width by thereduction in radius of the disc.

2. In a seal for-a bored housing and a cylindrical plunger, a flexible diaphragm which coniprises a radially slotted thin metallic disc, defining between said slots radially extending ribbons wider than the slots, each of the several ribbons having a loop portion with straight sides normal to the disc plane, the summation of the several loops forming an annular groove in the disc by which theoriginal diameter or the disc is rebonded to'the other 2,241,050 obvious those skilled in the art, after under an outer annulus to which the ends of said bons are bonded.

prising an inner annulus,

a plurality oi laterally contiguous independently flexible ribbons integral therewith and extending radially therefrom, and an outer annulusto which the ends of said ribbons are bonded. said ribbons having loops formed therein to define, in the aggregate, an annular groove between the inner and outer annuli. I

5. A diaphragm of thin flexible metal, comprising inner and outer annuli, and a plurality of lateral contiguous independently flexible sub-- stantially radially extending looped ribbons of thin metal bridging said annuli. the ribbons being integral with one said annulus and being overlapping the outer ends of said ribbons and bonded thereto.

duced in virtue of said loops; a re-eniorcing ring secured around the outer ends of said ribbons, said ring and the central portion oi said disc respectively engaging the housing and plunger and being adapted for axial displacement with consequent rolling shirt oi the loop-relative to the ring and central portion, the straight sides or the loops engaging the side walls of the housing and the plunger, said radial slots being reduced from their original width by the reduction in radius of the disc, and a rubber-like membrane conformed to said diaphragm and bridging said slots.

Y 3. A diaphragm'oi thin flexible metal com prising an inner annulus, a plurality oilaterally contiguous independently flexible ribbons integral therewith and extending radially therefrom. and

7. A re-eniorcing diaphragm for an elastic membrane of rubber or the like held between'an annular receptacle and a central plunger. and

subject to pressure on oneside thereof comprising a disc of thin resilient metal underlying the membrane and slotted radially inward from the disc periphery toward, but not to, the center, whereby radial ribbons'wlder than the slots are defined between the slots, each ribbon having a loop formed therein whereby the diameter oi the disc is substantially decreasedtrom its original diameter, said loops defining in the aggregate an annular groove into which said membrane may deform, and, a flat annulus of sheet metal -overlying and bonded to the outer ends or said ribbons, the central portion of said disc and said annulus thusforming arsubstantially rigid termini at the ends of each ribbon to which tensile stress a in the ribbons is transmitted upon imposition oi V ribbons.

pressure upon the membrane and diaphragm ROLAND CHILTON.

rib-

4. A diaphragm or thin flexible metal comsaid annular, the loops of the several ribbons deflning in the aggregate an 

